Means for visual inspection by comparison with a series of threedimensional pictures



Jan. 31, 1950 A. E. DENNIS 2,495,703

' MEANS FOR VISUAL INSPECTION BY COMPARISON WITH A SERIES 0F THREE-DIMENSIONAL PICTURES Filed Sept. 7, 1945 IN V EN TOR.

fl/eri Degplf BY ifzw KM iatented Jan. 31, 1950 UNITED MEANS FOR VISUAL INSPECTION BY COM- PARISON WITH A SERIES OF THREE- DIMENSIONAL PICTURES Albert E. Dennis, United States Army, Philadelphia, Pa.

Application September 7, 1945, Serial No. 615.059

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) Claims.

The invention described herein, if patented may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

My invention relates to means for expediting and facilitating the inspection of materials or objects for compliance with predetermined standards or to separate the sameinto categories based on appearance which is effected by using threedimensional color photographs produced by utilizing the characteristics of polarized light in lieu of actual samples of the material or object being inspected or graded.

Various methods of sampling, testing and inspecting goods of all kinds have been devised to determine compliance with conditions of contracts of purchase or for other purposes such as the separation of goods of the same class into different groups based on differences in appearance characteristics. In making an inspection for compliance with such conditions, samples of perfect speclments have at times been used to aid the inspector in determining whether or not the goods in question conform to these specimens, and although greater accuracy and uniformity are secured in the ordinary case when samples are used, yet samples of a good many types of materials lose much of their value after relatively short periods of use because they become worn or soiled and can no longer be relied on as accurate guides. Furthermore, actual samples are often bulky and inconvenient to use in actual practice, and if lost or destroyed may be diflicult to replace or reproduce To overcome these dililculties in carrying out inspections and comparisons of all kinds, I have devised an inspectors chart in which three-dimensional photographs of perfect specimens produced by utilizing the characteristics of polarized light are used in place of actual samples and are viewed through polarizing analyzers or glasses to bring out the visual characteristics of the material or article being tested or inspected, particularly the depth characteristics.

Accordingly, it is an object of the invention to provide new and improved means for inspecting materials and objects of all kinds to determine compliance with appearance characteristics or standards, or for separating them into different :ategories based on differences in appearance.

,A further object of the invention is the provi- :ion of new and improved means for making in- :pections or forseparating materials and objects nto categories based on appearance characterstics in which sets of standards or samples in" the form of threedimensional photographs of specimens produced by utilizing the characteristics of polarized light are used as substitutes for an actual sample of the material or object being tested or inspected in making inspections, tests or comparisons.

A still further object of the invention is the provision of new and improved means for making inspections or comparisons with respect to appearance characteristics in which three-dimensional photographs of actual specimens produced by utilizing the characteristics of polarized light are used in lieu of actual samples as a guide in making tests or inspections to determine compliance with established standards, so that the samples or standards do not suffer changes in appearance due to wear or soiling incident to use even after they have been used repeatedly.

Another object of the invention is the provision of a new and improved set of standards or samples to be used as a guide in making tests or in-= spections to determine compliance with estab lished standards which may be readily and inexpensively compiled, are durable in use and may be used repeatedly and, if desired, may be duplicated exactly and as frequently as necessary.

These and other objects of the invention will become apparent from the following description and accompanying drawing in which Figure 1 is a schematic diagram illustrating a method for carrying out an inspection of a material such as a fabric using a three-dimensional photograph of a specimen of the material as a sample for the purpose of comparison in lieu of an actual sample of the ,material.

Figure 2 is a schematic view of an arrangement of three-dimensional photographs adaptable for use in lieu of actual samples of the material being inspected for determining appearance characteristics, particularly those in which depth is a factor.

Figure 3 is a schematic view similar to Figure 2 but showing three-dimensional photographs arranged together to depict appearance characteristics ranging from satisfactory to non-satisfactory.

Referring to the drawing, I have diagrammatically shown the method used in making an inspection of a textile material such as the woolen goods used in making Army uniforms for winter wear. To be acceptable, such textiles must pass an inspection in which a number of characteristics such as its color, weight, texture, weave, etc. are examined. Many defects in addition to poor color can be observed upon such a visual inspection. particularly when the inspector hassampies oi specimens oi acceptable and non-acceptablequalityioruseinmakingacomparisonwith the material being inspected. Among the defects thusobservabie aresuchthingsassmallbreaks in the suriace or pick threads, excessively loose or open texture and excessive surface nap. The extent to which such defects may be present in a textile before they constitute grounds for relecting the same can best be determined by comparing the material being inspected with acceptable grades 01' the same type oi material. having varying degrees or defects along with a periect sample and a sample oi the material so deiective as to be clearly non-acceptable. Alter comparison with these samplesI it is relatively easy to place the material being inspected in its proper category. However, a difllculty arises in the use oi actual samples oi material because they soon become worn and soiled and thus in the hands oi diiierent inspectors lose their uni;- iormity as because the wear and soiling will not be the same in each sample.

My invention is aimed at overcoming these disadvantages in the use oi actual samples. Heretoiore, the Polaroid Corporation developed and patented the method, mechanism and materials used in producing three-dimensional photographs in color utilizing polarized light along with analyzers or glasses to be used in viewing these photographs. I have iound that photographs made in accordance with these teachingsmay' be used to advantage in place oi actual samples in making up sets oi standards or samples ior use by inspectors, but a certain method must be followed in their use it accurate results are to be obtained with them. Although a single photograph oi this type of the object being inspected is sumcient where it is sought only to convey an ii a larger number oi photographs or specimens oi the material or object ranging from acceptable to non-acceptable are made up as a guide so that an impression oi the range. oi defeotiveness or deviation from perfection whichmay exist beiore a material or object is subject to rejection is conveyed. To convey this impression it has been iound necessary to include as part of the sample or chart a photograph or a perfect sample and a photograph oi a sample defective to a degree suiflclent to clearly place it in a group relectable on that ground. Preferably one or more additional hotographs are included on the chart or standard oi samples in the range oi detectiveness and periection represented by the first two photographs to aid inspectors in making a determination.

In Figure 1 oi the drawing. I have illustrated a method oi carrying out the invention where it is desired merely to show the appearance of an obiect or body including its three-dimensional characteristics. In this figure, a three-dimensional photograph or a periect specimen oi'the particular object or body is indicated at ll mounted on a chart or backing H. In use this photograph is viewed through analyzers or glasses ll oi the type manufactured by the Polaroid Corporation having lenses which are polarized in planes normal to each other. when viewed through these analyzers the three-dimensional characteristics of the object in the photograph II are brought out so that it has the same apaeeavoa 4 v ry accurate impression oi the actual appear- .ance oi the oblect is conveyed.

it it is desired to compare the appearance oi some part oi an object of the type depictedin the photograph with a peri'ect specimen, this can be done by placing the object ll. ior example, a man's shirt, adjacent to photograph ll of a shirt or this type perfect in construction and viewing both through the analysers ll. The three-dimensional characteristics oi the photograph, are brought out, but the appearance oithe actual obiect is not aiiected by the analyzers so that an accurate comparison between the two can be made at least with respect to depth characteristics. The degree oi accuracy and uniformity achieved by this method oi comparison iar exceeds that obtained when no standard or sample is used, because the inspector's conception oi the appearance oi the object is not based on descrip tion or memory alone, but is based upon a perception oi the actual appearance oi the object secured by viewing the three-dimensional photograph III.

However. the single-photograph 0! Figure 1 does not give any conception oi the range oi appearance characteristics which may occur, or the extent to which a material or object may be defective and yet be acceptable. In Figure 2 I have illustrated an inspector's chart or sample in which in additionto a photograph H of a perfect specimen a second photograph ii is included, depicting a specimen oi the same material or object as shown in photograph l4, but having defects of a degree sumcientto place the material or object in a class failing to comply with minimum standards of acceptability. When two photographs of the type described areincluded on a single chart and viewed through analyzers IS. an impression is conveyed thereby oi the range oi appearance characteristics which may occur in the given material or object. but the part or the range within which materials may iall and still be acceptable is not indicated.

A means ior clearly defining this latter range in appearance is shown in Figure 3 wherein in addition to the two photographs I. and II shown in Figure 2, a third photograph It is included on a chart or backing II. This is a photograph of a sample oi material having defects in appearancl oi a degree suilicient to place it on the borde1 line of acceptability. Thus, any sample of mate rial not equalling the photograph It in appear ance when viewed through analyzers II is reject able and any sample in the range of appearanc between the photograph l4 oi a perfect specimel and the photograph It of a border line specimel is clearly acceptable.

In order to facilitate the use oi these sample or standards in making .an inspection the thrs photographs ll, II and it are mounted side 11 side on a single backin sheet such as the cha: II as shown in Figure 8 with the proper legen V to identity each oi them. I: this is a, chart n use in inspecting a textile, then the textile 1 can be partly overlaid on the photographs whi they are being viewed through the polarizii analyzers ll.

The important consideration in making 1 charts for the guidance of inspectors is that th contain photographs 0! more than one specim oi the particular type of material being inspect so that together they show varying degrees defectiveness and also the limit oi deiectivem beyond which a material is subject to reject! pearance as the actual object. In this manner, a It so that the inspector has an accurate and lie ible guide. since any number of prints desired can be made from a single negative, it will be obvious that any number of inspectors charts may be made up and all of these charts will be uniform and will remain so, even after extended use, so that all inspectors are aided in their work by uniform guides with the result that a greater degree of uniformity in inspections can be achieved as between different inspectors.

While the invention has been described as applied to the inspection of textile materials, it will be obvious that the same principles may be advantageously applied wherever materials or ob- Jects are to be divided into different categories based on differences in appearance characteristics. Three-dimensional photographs made and compiled in accordance with the teachings of this invention may be used in lieu of actual samples so that the photograph itself becomes the sample in all procedures where it becomes necessary to demonstrate workmanship, physical appearance and other variable characteristics which cannot be definitely described by words or clearly shown in the ordinary photograph. In other words, these photographs are useful wherever samples have previously been used to show appearance characteristics and they may be used in lieu of actual samples by salesmen, inspectors. or others who commonly use samples in the conduct of their business.

While a preferred embodiment of the invention has been shown and described, it is to be understood that modifications may be made therein and that protection is sought for all such modifications coming within the scope of the appended claims.

Iclaim:

1. An inspectors chart for side by side visual comparison with the surface of a three-dimensional object, said chart comprising a plurality of three-dimensional photographs of specimens corresponding to such three-dimensional ob- Ject, said three-dimensional photographs being mounted on a backin in assembled relation, each of said three-dimensional photographs producing a depth image when viewed through an analyzer, at least one of said three-dimensional photographs being the photograph of an imperfeet but acceptable specimen having physical three-dimensional surface characteristics placing it not below the borderline of a predetermined standard of acceptability, and at least one other of said three-dimensional photographs be ing the photograph of an imperfect and unacceptable specimen having physical three-dimensional surface characteristics placing it below the borderline of said predetermined standard of acceptability; whereby the acceptability of such object in accordance with its visually observable three-dimensional surface characteristics may be determined.

2. An inspectors chart for side by side visual comparison with the surface of a three-dimensional object, said chart comprising a plurality of three-dimensional photographs of specimens corresponding to such three-dimensional object, said three-dimensional photographs being mounted on a backing in assembled relation, each of said three-dimensional photographs producing a depth image when viewed through an analyzer, one of said three-dimensional photographs being the photograph of an imperfect but acceptable specimen having physical threedimensional surface characteristics placing it on the borderline of a predetermined standard of 6 acceptability, and at least one other of said threedimensional photographs being the photograph predetermined standard of acceptability; whereby the acceptability of such object in accordance with its visually observable three-dimensional surface characteristics may be determined.

3. An inspector's chart for side by side visual comparison with the surface of a three-dimensional object, said chart comprising a plurality of three-dimensional photographs of specimens corresponding to such three-dimensional object, said three-dimensional photographs being mounted on a backing in assembled relation, each of said three-dimensional photographs producing a depth image when viewed through an analyzer, one of said three-dimensional photographs being the photograph of a specimen hav ing substantially perfect physical three-dimensional surface characteristics, at least one other of said three-dimensional photographs being the photograph of an imperfect but acceptable specimen having physical three-dimensional surface characteristics placing it on the borderline of a predetermined standard of acceptability, and at least one other of said three-dimensional photographs being the photograph of an imperfect and unacceptable specimen having physical three-dimensional surface characteristics placing it below the borderline of said predetermined standard of acceptability; whereby the acceptability of such object in accordance with its visually observable three-dimensional surface characteristics may be determined.

4. An inspector's chart for side by side visual comparison with the surface of a three-dimensional object, said chart comprising a plurality of three-dimensional light-polarizing photographs of specimens corresponding to such three-dimem sional object, said three-dimensional photographs being mounted on a backing in assembled relation, each of said three-dimensional photographs producing a depth image when viewed through an analyzer, at least one of said threedimensional photographs being the photograph of an imperfect but acceptable specimen having physical three-dimensional surface characteristics placin it not below the borderline of a predetermined standard of acceptability, and at least one other of said three-dimensional photographs being the photograph of an imperfect and unacceptable specimen having physical three-dimensional surface characteristics placing it below the borderline of said predetermined standard of acceptability; whereby the acceptability of such object in accordance with its visually observable three-dimensional surface characteristics may be determined.

5. An inspector's chart for side by side visual comparison with the surface of a three-dimensional object, said chart comprising a plurality of three-dimensional light-polarizing color photographs of specimens corresponding to such threedimensional object, said three-dimensional photographs being mounted on a backing in assembled relation, each of said three-dimensional photographs prdoucing a depth image when viewed through an analyzer, at least one of said three-dimensional photographs being the photograph of an imperfect but acceptable specimen having physical three-dimensional surface characteristics placing it not below the borderline of a predetermined standard of acceptability. and

atleastoneotherofs'aldpho *tographabelnstMphotdsflWdtnhnMhfl m and unacceptable specimen 1mm dulled Name Date three-dimensional aux-I'm M. 708,319 121mm June 24, 1902 in; it below the hardening of aid predetermined 5 1.561.781 Smith Nov. 1'1, 1925 standard of acceptability: wlm-eby the accepta- 2,203,687 14nd ea 51. June 11, 1840 bility of suchblobject in fifth its via 2,397,272 land Mar.- 28, 1946 uallyobserva ethreeanal weal!!!- 1 acterlstics may be determined. 7 m A cm ALBEBTlbINNIB. l0 and Lomb Publication 5-216; publubed mo 4 pa es). REFERENCES crrm The following refei'enoes 'are of feoord in m tile 0! this patent: 

